/* ============================================================
   MECHANICAL BALLET — ink on drafting paper
   palette: paper #f3eee1 · paper-2 #eae2cf · ink #232b33
            ink-soft #66717d · construction #98a1ab
            vermillion #c2452d · blueprint #39597c
   ============================================================ */
:root{
  --paper:#f3eee1;
  --paper-2:#eae2cf;
  --ink:#232b33;
  --ink-soft:#66717d;
  --line:#98a1ab;
  --red:#c2452d;
  --blue:#39597c;
  --frame:18px;
  --mono:'IBM Plex Mono',ui-monospace,monospace;
  --serif:'Fraunces',Georgia,serif;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion: reduce){ html{scroll-behavior:auto} }

body{
  background:
    radial-gradient(1300px 900px at 75% -10%, rgba(255,255,255,.55), transparent 60%),
    linear-gradient(rgba(35,43,51,.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(35,43,51,.05) 1px, transparent 1px),
    var(--paper);
  background-size:auto, 56px 56px, 56px 56px, auto;
  color:var(--ink);
  font-family:var(--serif);
  font-optical-sizing:auto;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
}
::selection{background:var(--red);color:var(--paper)}
:focus-visible{outline:2px solid var(--red);outline-offset:3px}
html{scrollbar-width:thin;scrollbar-color:var(--ink) var(--paper-2)}
body::-webkit-scrollbar{width:10px}
body::-webkit-scrollbar-track{background:var(--paper-2)}
body::-webkit-scrollbar-thumb{background:var(--ink);border:2px solid var(--paper-2)}
.mono{font-family:var(--mono)}
.dim-txt{color:var(--ink-soft)}

/* grain */
.grain{
  position:fixed;inset:0;z-index:40;pointer-events:none;opacity:.5;
  mix-blend-mode:multiply;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='240' height='240'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix values='0 0 0 0 0.14 0 0 0 0 0.17 0 0 0 0 0.2 0 0 0 0.05 0'/%3E%3C/filter%3E%3Crect width='240' height='240' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* drawing frame around the viewport */
.frame{
  position:fixed;inset:var(--frame);z-index:30;pointer-events:none;
  border:1.5px solid var(--ink);
}
.frame::after{
  content:"";position:absolute;inset:5px;border:.75px solid rgba(35,43,51,.5);
}
.frame .zone{
  position:absolute;font-family:var(--mono);font-size:9px;letter-spacing:.1em;
  color:var(--ink-soft);
}
.frame .zone.zx{top:-14px;transform:translateX(-50%)}
.frame .zone.zy{left:-13px;transform:translateY(-50%)}

/* masthead */
.masthead{
  position:fixed;top:var(--frame);left:var(--frame);right:var(--frame);z-index:50;
  display:flex;justify-content:space-between;align-items:center;gap:18px;
  font-size:11px;letter-spacing:.14em;
  padding:11px 20px 10px;
  background:rgba(243,238,225,.88);
  -webkit-backdrop-filter:blur(6px);backdrop-filter:blur(6px);
  border-bottom:1.5px solid var(--ink);
}
.masthead a{
  color:var(--ink);text-decoration:none;border-bottom:1px solid var(--red);
  padding-bottom:2px;transition:color .25s ease,border-color .25s ease;
}
.masthead a:hover{color:var(--red)}
.mast-id{white-space:nowrap}
.sheet-nav{display:flex;align-items:baseline;gap:18px;overflow-x:auto;scrollbar-width:none}
.sheet-nav::-webkit-scrollbar{display:none}
.sheet-nav a{
  font-size:9.5px;letter-spacing:.16em;color:var(--ink-soft);
  border-bottom:1px solid transparent;white-space:nowrap;padding-bottom:3px;
}
.sheet-nav a:hover{color:var(--red);border-color:var(--red)}
.sheet-nav a.is-active{color:var(--ink);border-color:var(--red)}
.sheet-nav .nav-guide{color:var(--ink);border-bottom:1px solid var(--red);font-size:9.5px}
.sheet-nav .nav-guide:hover{color:var(--red)}

/* scroll progress — a plotting rule under the masthead */
.progress{
  position:fixed;top:calc(var(--frame) + 40px);left:var(--frame);right:var(--frame);
  height:2px;z-index:49;pointer-events:none;
}
.progress span{
  display:block;height:100%;background:var(--red);
  transform:scaleX(0);transform-origin:left center;
}

/* sections clear the fixed masthead when anchored */
section[id],footer[id]{scroll-margin-top:86px}

main{position:relative;z-index:10}

/* ============ HERO ============ */
.hero{
  min-height:100vh;position:relative;
  display:flex;flex-direction:column;
  padding:calc(var(--frame) + 78px) calc(var(--frame) + 30px) 0;
  overflow:hidden;
}
.bg-gear{
  position:absolute;top:-190px;right:-170px;width:620px;height:620px;
  opacity:.55;pointer-events:none;
}
.hero-head{position:relative;z-index:3;max-width:860px;pointer-events:none}
.hero-head a{pointer-events:auto}
.overline{
  font-size:11px;letter-spacing:.22em;color:var(--ink-soft);
  margin-bottom:22px;
}
.title{
  font-weight:300;
  font-size:clamp(64px, 10.5vw, 152px);
  line-height:.92;letter-spacing:-.02em;
  font-variation-settings:'opsz' 144;
}
.title .mask{display:block;overflow:hidden;padding-bottom:.06em;margin-bottom:-.06em}
.title .line{display:inline-block}
.title .it{font-style:italic;font-weight:400;color:var(--ink);margin-left:.35em}
.title .it::after{
  content:"";display:inline-block;width:.55em;height:2px;background:var(--red);
  vertical-align:.28em;margin-left:.18em;
}
.lede{
  margin-top:26px;max-width:460px;
  font-size:16.5px;line-height:1.6;color:var(--ink-soft);
}
.stage{
  position:absolute;inset:0;z-index:2;
  top:calc(var(--frame) + 50px);bottom:6px;
}
.stage svg{position:absolute;inset:0;width:100%;height:100%}

/* transport */
.transport{
  position:absolute;z-index:5;
  left:calc(var(--frame) + 30px);bottom:calc(var(--frame) + 26px);
  display:flex;align-items:stretch;gap:0;
  border:1.5px solid var(--ink);background:var(--paper);
  box-shadow:4px 4px 0 rgba(35,43,51,.12);
}
.play-btn{
  width:52px;border:none;border-right:1.5px solid var(--ink);
  background:var(--ink);cursor:pointer;display:grid;place-items:center;
  transition:background .25s ease;
}
.play-btn svg{width:16px;height:16px;fill:var(--paper)}
.play-btn:hover{background:var(--red)}
.play-btn .ic-play{display:none}
.play-btn.is-paused .ic-play{display:block}
.play-btn.is-paused .ic-pause{display:none}
.t-cell{
  display:flex;flex-direction:column;justify-content:center;gap:3px;
  padding:9px 16px;border-right:1.5px solid var(--ink);min-width:190px;
}
.t-rpm{min-width:120px}
.t-label{font-size:8.5px;letter-spacing:.18em;color:var(--ink-soft)}
.t-value{font-size:12px;letter-spacing:.08em;font-weight:500}
#movName{color:var(--red)}
#dial{width:84px;height:52px;align-self:center;margin:0 6px}

.scroll-cue{
  position:absolute;z-index:5;right:calc(var(--frame) + 34px);
  bottom:calc(var(--frame) + 34px);
  font-size:10px;letter-spacing:.2em;color:var(--ink-soft);
}
.cue-arrow{display:inline-block;margin-left:8px;color:var(--red)}
@media (prefers-reduced-motion: no-preference){
  .cue-arrow{animation:cue 2.2s ease-in-out infinite}
}
@keyframes cue{0%,100%{transform:translateY(0)}50%{transform:translateY(5px)}}

/* ============ ACTS ============ */
.act{padding:120px calc(var(--frame) + 30px) 40px;position:relative}
.act-rule{
  display:flex;align-items:center;gap:18px;
  color:var(--ink-soft);font-size:10px;letter-spacing:.2em;
  margin-bottom:64px;
}
.act-rule::before,.act-rule::after{
  content:"";flex:1;height:1px;
  background:repeating-linear-gradient(90deg, var(--line) 0 14px, transparent 14px 19px, var(--line) 19px 22px, transparent 22px 27px);
}
.act-grid{
  display:grid;grid-template-columns:minmax(300px,5fr) 7fr;
  gap:56px;align-items:center;max-width:1280px;margin:0 auto;
}
.act-flip .act-grid{grid-template-columns:7fr minmax(300px,5fr)}
.act-flip .act-copy{order:2}
.act-flip .act-fig{order:1}
.act-no{
  font-size:11px;letter-spacing:.26em;color:var(--red);margin-bottom:14px;
}
.act-no::after{
  content:"";display:inline-block;width:44px;height:1px;background:var(--red);
  vertical-align:.32em;margin-left:12px;
}
.act-title{
  font-weight:300;font-style:italic;
  font-size:clamp(42px,4.6vw,64px);line-height:1.02;letter-spacing:-.015em;
  font-variation-settings:'opsz' 144;
  margin-bottom:22px;
}
.act-sub{
  display:block;font-style:normal;font-weight:400;
  font-size:clamp(17px,1.5vw,21px);letter-spacing:.01em;
  color:var(--ink-soft);margin-top:10px;
}
.act-text{font-size:16px;line-height:1.65;color:#3a444e;max-width:44ch}
.act-text em{color:var(--red)}
.spec{
  margin-top:28px;border-top:1.5px solid var(--ink);max-width:400px;
}
.spec > div{
  display:flex;justify-content:space-between;gap:16px;
  padding:8px 2px;border-bottom:1px solid rgba(35,43,51,.25);
  font-size:11px;letter-spacing:.06em;
}
.spec dt{color:var(--ink-soft)}
.spec dd{text-align:right;font-weight:500}
.act-fig svg{width:100%;height:auto;display:block}

/* ============ SVG drawing classes ============ */
svg text{font-family:var(--mono)}
.lbl{font-size:10.5px;fill:var(--ink-soft);letter-spacing:.09em}
.lbl-strong{fill:var(--ink);font-weight:500}
.lbl-red{fill:var(--red)}
.lbl-big{font-size:13px}
.gear-body{fill:var(--paper);stroke:var(--ink);stroke-width:1.6}
.gear-body.acc{stroke-width:2}
.hub{fill:var(--paper);stroke:var(--ink);stroke-width:1.4}
.bore{fill:none;stroke:var(--ink);stroke-width:1.1}
.spoke{stroke:var(--ink);stroke-width:1.3;fill:none}
.pitch{fill:none;stroke:var(--red);stroke-width:.8;stroke-dasharray:10 4 2 4;opacity:.6}
.cl{stroke:var(--line);stroke-width:.9;fill:none;stroke-dasharray:15 5 3 5}
.thin{stroke:var(--ink-soft);stroke-width:.9;fill:none}
.faint{stroke:var(--line);stroke-width:.8;fill:none}
.link{stroke:var(--ink);stroke-width:5;stroke-linecap:round;fill:none}
.link-lt{stroke:var(--ink);stroke-width:3;stroke-linecap:round;fill:none}
.coupler-web{fill:rgba(35,43,51,.06);stroke:var(--ink);stroke-width:1.6;stroke-linejoin:round}
.pin{fill:var(--paper);stroke:var(--ink);stroke-width:1.4}
.pin-dot{fill:var(--ink)}
.index{fill:var(--red)}
.trace{fill:none;stroke:var(--red);stroke-width:1.6;opacity:.9;stroke-linejoin:round}
.ghost{stroke:var(--line);opacity:.55;stroke-width:1.1;fill:none;stroke-linecap:round}
.ghost-pt{fill:var(--line);opacity:.7}
.dim{stroke:var(--ink-soft);stroke-width:.9;fill:none}
.body-fill{fill:var(--paper);stroke:var(--ink);stroke-width:1.6}
.body-dark{fill:var(--paper-2);stroke:var(--ink);stroke-width:1.6}
.hatched{fill:url(#hatch);stroke:var(--ink);stroke-width:1.4}
.hatch-line{stroke:var(--line);stroke-width:1;fill:none}
.needle{stroke:var(--red);stroke-width:2;stroke-linecap:round}
.an-act{stroke:var(--blue);stroke-width:1.8;fill:none}
.tempo-curve{stroke:var(--red);stroke-width:1.8;fill:none;stroke-linejoin:round}
.pulse-ring{fill:none;stroke:var(--red);stroke-width:2;opacity:0}

/* spec rows — hover feedback */
.spec > div{transition:background .25s ease}
.spec > div:hover{background:rgba(194,69,45,.06)}
.spec > div:hover dd{color:var(--red)}
.spec dd{transition:color .25s ease}

/* ============ ANATOMY — pinned mesh detail ============ */
.anatomy{position:relative}
.pin-stage{
  min-height:100vh;display:flex;flex-direction:column;justify-content:center;
  padding:calc(var(--frame) + 70px) calc(var(--frame) + 30px) 30px;
}
.pin-stage .act-rule{margin-bottom:40px}
.anatomy-grid{
  display:grid;grid-template-columns:minmax(300px,4.5fr) 7.5fr;
  gap:56px;align-items:center;max-width:1320px;margin:0 auto;width:100%;
}
.anatomy-fig svg{width:100%;height:auto;display:block}
.an-steps{list-style:none;margin-top:30px;border-top:1.5px solid var(--ink);max-width:400px}
.an-steps li{
  font-size:10.5px;letter-spacing:.14em;color:var(--line);
  padding:9px 2px;border-bottom:1px solid rgba(35,43,51,.18);
  transition:color .35s ease,padding-left .35s ease;
  position:relative;
}
.an-steps li::before{
  content:"";position:absolute;left:0;top:50%;width:0;height:1.5px;
  background:var(--red);transition:width .35s ease;
}
.an-steps li.is-on{color:var(--ink);padding-left:20px}
.an-steps li.is-on::before{width:12px}
.an-meter{
  display:flex;align-items:center;gap:12px;margin-top:22px;max-width:400px;
  font-size:9.5px;letter-spacing:.18em;color:var(--ink-soft);
}
.an-bar{
  flex:1;height:4px;border:1px solid var(--ink);background:var(--paper);
  overflow:hidden;
}
.an-bar i{
  display:block;height:100%;background:var(--red);
  transform:scaleX(0);transform-origin:left center;
}
.an-pct{min-width:38px;text-align:right;color:var(--ink);font-weight:500}

/* ============ SCORE ============ */
.score{padding:130px calc(var(--frame) + 30px) 60px}
.score .act-rule{margin-bottom:64px}
.score-grid{
  display:grid;grid-template-columns:6fr 6fr;gap:64px;align-items:start;
  max-width:1280px;margin:0 auto;
}
.tempo-wrap{
  margin-top:30px;border:1.5px solid var(--ink);background:var(--paper);
  box-shadow:4px 4px 0 rgba(35,43,51,.12);padding:14px 12px 8px;
}
.tempo-wrap svg{width:100%;height:auto;display:block}
.score-table{display:flex;flex-direction:column;border-top:1.5px solid var(--ink)}
.mov-row{
  display:grid;grid-template-columns:44px 1fr auto 84px;align-items:baseline;gap:14px;
  padding:15px 10px 15px 14px;border:none;border-bottom:1px solid rgba(35,43,51,.25);
  background:transparent;cursor:pointer;text-align:left;
  font-size:11px;letter-spacing:.1em;color:var(--ink);
  position:relative;transition:background .25s ease;
}
.mov-row::before{
  content:"";position:absolute;left:0;top:0;bottom:-1px;width:3px;
  background:var(--red);transform:scaleY(0);transform-origin:top center;
  transition:transform .3s cubic-bezier(.2,.8,.2,1);
}
.mov-row:hover{background:rgba(35,43,51,.045)}
.mov-row:active{background:rgba(194,69,45,.09)}
.mov-row.is-now{background:rgba(194,69,45,.06)}
.mov-row.is-now::before{transform:scaleY(1)}
.mv-no{color:var(--red);font-weight:600;letter-spacing:.14em}
.mv-name{
  font-family:var(--serif);font-style:italic;font-weight:400;
  font-size:21px;letter-spacing:0;line-height:1;
}
.mv-mark{font-size:9px;letter-spacing:.2em;color:var(--ink-soft)}
.mv-rpm{text-align:right;font-size:10.5px;font-weight:500}
.mov-row.is-now .mv-mark{color:var(--red)}
.score-hint{
  font-size:9px;letter-spacing:.2em;color:var(--ink-soft);
  padding:12px 2px 0;
}

/* ============ COLOPHON ============ */
.colo{padding:130px calc(var(--frame) + 30px) 20px}
.colo .act-rule{margin-bottom:64px}
.colo-grid{
  display:grid;grid-template-columns:1fr 1fr;gap:64px;
  max-width:1280px;margin:0 auto;align-items:start;
}
.legend{list-style:none;border-top:1.5px solid var(--ink)}
.legend li{
  display:grid;grid-template-columns:110px 1fr;gap:18px;align-items:center;
  padding:12px 6px;border-bottom:1px solid rgba(35,43,51,.18);
  transition:background .25s ease;
}
.legend li:hover{background:rgba(35,43,51,.045)}
.legend svg{width:96px;height:14px;overflow:visible}
.legend li:hover .cl,.legend li:hover .dim,.legend li:hover .ghost,
.legend li:hover .hatch-line{stroke:var(--red)}
.legend .cl,.legend .dim,.legend .ghost,.legend .hatch-line{transition:stroke .25s ease}
.legend b{display:block;font-size:10px;letter-spacing:.16em;font-weight:600}
.legend span{display:block;font-size:12.5px;color:var(--ink-soft);font-style:italic;margin-top:2px}
.rev{
  border-collapse:collapse;width:100%;font-size:10px;letter-spacing:.06em;
  border:1.5px solid var(--ink);background:var(--paper);
  box-shadow:4px 4px 0 rgba(35,43,51,.12);
}
.rev th{
  font-size:8.5px;letter-spacing:.2em;color:var(--ink-soft);font-weight:500;
  border:1px solid rgba(35,43,51,.5);padding:7px 10px;text-align:left;
}
.rev td{border:1px solid rgba(35,43,51,.5);padding:9px 10px;line-height:1.55;vertical-align:top}
.rev td:first-child{color:var(--red);font-weight:600}
.rev tr{transition:background .2s ease}
.rev tr:hover td{background:rgba(35,43,51,.035)}
.instruments-head{margin-top:38px}
.cred{list-style:none;border-top:1.5px solid var(--ink)}
.cred li{
  font-size:10.5px;letter-spacing:.08em;line-height:1.6;color:var(--ink-soft);
  padding:10px 2px;border-bottom:1px solid rgba(35,43,51,.18);
}
.cred b{color:var(--ink);font-weight:600;letter-spacing:.12em}

.foot-strip{
  grid-column:1 / -1;margin-top:46px;padding-top:16px;
  border-top:1px solid rgba(35,43,51,.35);
  font-size:9px;letter-spacing:.18em;color:var(--ink-soft);
}

/* ============ TITLE BLOCK ============ */
.titleblock{
  margin:140px calc(var(--frame) + 30px) calc(var(--frame) + 40px);
  display:grid;grid-template-columns:1.2fr 1fr;gap:48px;
  max-width:1280px;margin-left:auto;margin-right:auto;
  padding:0 calc(var(--frame) + 30px) calc(var(--frame) + 50px);
  align-items:end;
}
.notes-head{font-size:11px;letter-spacing:.22em;color:var(--red);margin-bottom:14px}
.notes ol{list-style:none;counter-reset:n}
.notes li{
  counter-increment:n;font-size:11px;line-height:1.7;letter-spacing:.05em;
  color:var(--ink-soft);margin-bottom:8px;padding-left:26px;position:relative;
}
.notes li::before{
  content:counter(n) ".";position:absolute;left:0;color:var(--ink);font-weight:500;
}
.guide-link{
  display:inline-block;margin-top:34px;text-decoration:none;color:var(--ink);
  border:1.5px solid var(--ink);padding:16px 26px 18px;background:var(--paper);
  box-shadow:4px 4px 0 rgba(35,43,51,.14);
  transition:transform .3s cubic-bezier(.2,.8,.2,1), box-shadow .3s cubic-bezier(.2,.8,.2,1), background .3s;
}
.guide-link:hover{
  transform:translate(-2px,-2px);box-shadow:7px 7px 0 rgba(194,69,45,.28);
}
.guide-link .mono{display:block;font-size:9.5px;letter-spacing:.24em;color:var(--red);margin-bottom:6px}
.gl-big{font-size:26px;font-style:italic;font-weight:300}
.tb{
  border-collapse:collapse;width:100%;font-size:11px;letter-spacing:.06em;
  border:1.5px solid var(--ink);background:var(--paper);
  box-shadow:4px 4px 0 rgba(35,43,51,.12);
}
.tb td{border:1px solid var(--ink);padding:9px 14px}
.tb-label{color:var(--ink-soft);font-size:9px;letter-spacing:.18em;width:70px}
.tb-title{font-size:14px;font-weight:600;letter-spacing:.2em}

/* pre-hidden elements until intro (JS present only) */
.js [data-pre]{visibility:hidden}
.js #ensemble{visibility:hidden}
@media (prefers-reduced-motion: reduce){
  .js [data-pre], .js #ensemble{visibility:visible}
}

/* ============ RESPONSIVE ============ */
@media (max-width:980px){
  .act-grid, .act-flip .act-grid{grid-template-columns:1fr;gap:36px}
  .act-flip .act-copy{order:1}
  .act-flip .act-fig{order:2}
  .titleblock{grid-template-columns:1fr;gap:40px}
  .anatomy-grid{grid-template-columns:1fr;gap:36px}
  .pin-stage{justify-content:flex-start;padding-top:calc(var(--frame) + 84px)}
  .score-grid,.colo-grid{grid-template-columns:1fr;gap:48px}
}
@media (max-width:720px){
  :root{--frame:10px}
  .masthead{font-size:9px;letter-spacing:.1em;padding:9px 12px 8px;gap:12px}
  .mast-id{display:none}
  .sheet-nav{gap:14px;width:100%}
  .sheet-nav a{font-size:8.5px}
  .progress{top:calc(var(--frame) + 34px)}
  .hero{padding:calc(var(--frame) + 64px) calc(var(--frame) + 14px) 0}
  .lede{font-size:15px}
  .stage{top:auto;height:44vh;bottom:76px}
  .transport{left:calc(var(--frame) + 10px);right:calc(var(--frame) + 10px);bottom:calc(var(--frame) + 12px)}
  .t-cell{min-width:0;flex:1;padding:8px 10px}
  .t-rpm{display:none}
  #dial{display:none}
  .scroll-cue{display:none}
  .act{padding:80px calc(var(--frame) + 14px) 30px}
  .pin-stage{padding:calc(var(--frame) + 58px) calc(var(--frame) + 14px) 24px}
  .pin-stage .act-rule{margin-bottom:22px}
  .anatomy .act-text{display:none}
  .anatomy .act-title{font-size:34px;margin-bottom:8px}
  .anatomy-grid{gap:18px}
  .an-steps{margin-top:12px}
  .an-steps li{padding:7px 2px;font-size:9.5px}
  .an-meter{margin-top:14px}
  .score,.colo{padding-left:calc(var(--frame) + 14px);padding-right:calc(var(--frame) + 14px);padding-top:90px}
  .mov-row{grid-template-columns:34px 1fr auto;gap:10px}
  .mv-rpm{display:none}
  .mv-name{font-size:18px}
  .legend li{grid-template-columns:80px 1fr;gap:12px}
  .legend svg{width:74px}
  .titleblock{padding:0 calc(var(--frame) + 14px) calc(var(--frame) + 40px);margin-top:90px}
  .frame .zone{display:none}
}